/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements. See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership. The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License. You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied. See the License for the
 * specific language governing permissions and limitations under the License.
 */
package org.apache.shindig.gadgets.http;

import com.google.inject.ImplementedBy;

/**
 * Cache of HttpResponse.
 *
 * Keys are HttpRequest, values are the HttpResponse.
 */
@ImplementedBy(DefaultHttpCache.class)
public interface HttpCache {

  HttpResponse getResponse(HttpRequest request);

  /**
   * Add a request/response pair to the cache.
   * 
   * @return true if the response was cached, false if the response was not cached.
   */
  boolean addResponse(HttpRequest request, HttpResponse response);

  HttpResponse removeResponse(HttpRequest key);
  
  /**
   * Create a string representation of the cache key.  If two requests are cache equivalent (a
   * response to one request can be used to respond to the other request), their keys are
   * guaranteed to be identical.
   * 
   * Identical keys do not guarantee that two requests are cache equivalent.
   */
  String createKey(HttpRequest request);
}
